1. Field of the Invention
The present invention relates to a video recording apparatus that records video such as footage acquired by a digital video camera, as well as to a video recording method, and a recording medium. More particularly, the present invention relates to a video recording apparatus, a video recording method, and a recording medium whereby acquired footage or other video is recorded using image recognition technology, such as face detection and facial recognition.
More specifically, the present invention relates to a video recording apparatus, a video recording method, and a recording medium whereby partial images made up of a partial area containing a feature point such as a person's face are recorded from original images that were acquired at a resolution higher than the pixel count used for video recording. More particularly, the present invention relates to a video recording apparatus, a video recording method, and a recording medium whereby partial images containing a feature point desired by the user are recorded from original images containing a plurality of such feature points.
2. Description of the Related Art
Digital cameras have come into widespread use. Digital cameras digitize images captured by a solid-state imaging sensor such as a CCD (charge-coupled device) or CMOS (complementary metal-oxide semiconductor). By means of such digital cameras, digitally encoded images can be stored in memory and then be processed or managed on a computer, without the problems related to film life. When a hard disk is included in the recording component of a digital video camera, it is possible to digitally record large amounts of high-quality image data, and later randomly access recorded data. Furthermore, such a digital video camera can be connected to a computer to enable file operations and image or video editing on the computer.
Technology for automating camera work has been introduced into digital cameras. For example, there exist functions for auto focus (AF), auto exposure (AE), image stabilization, and auto shutter. Processing such as that for AF and AE have the advantage of being realized by means of digital processing, rather than by camera optics. In addition, by using digital processing to perform image quality adjustments with respect to acquired footage, a suitable color state can be reproduced. For example, auto white balance (AWB) may be used to apply white balance gain to acquired footage.
Furthermore, image recognition engines have recently come to be incorporated into digital cameras. By means of such image recognition engines, areas containing feature points can be specified within the acquired footage. The feature points referred to herein can take on various meanings, but principally refer to human faces. The introduction of facial recognition technology into digital cameras is founded upon the large number of cases wherein people, and particularly their faces, wholly constitute the photographic subject. Image recognition can thus lead to the development of technology for improving the image quality of the portions of images containing people and their faces. For example, on the basis of facial recognition results, the focus may be automatically matched to a face, or alternatively, the image quality may be automatically corrected to match the face.
In digital cameras, it is typical to acquire images at a resolution higher than the pixel count used for video recording. Utilizing the above, it is possible to detect the area containing faces or people within an image, and subsequently perform high quality partial encoding or partial enlargement and encoding of the detected area. In so doing, faces can be recorded sharply and distinctly (see Japanese Unexamined Patent Application Publication No. 2003-219396, for example).
In addition, a video recording apparatus has been proposed having the following: imaging means for imaging at a resolution higher than the pixel count used for video recording; full image generating means for resolution-converting the original image obtained by imaging into a full image having the pixel count used for video recording; partial image generating means for generating an image having the pixel count used for video recording from a portion of the original image; and recording means for recording, in association with each other, a full video made up of full images, and a partial video made up of partial images (see Japanese Unexamined Patent Application Publication No. 2006-109119, for example). According to the above video recording apparatus, by simply acquiring footage with the overall state contained in the field of view, both overall and partial (i.e., zoomed-in) videos are automatically recorded. For this reason, acquiring and recording footage can be simplified, without zooming or similar operations being performed by the camera operator. Furthermore, facial recognition technology may be used to generate partial images containing faces of large size appearing in the original images, or to generate partial images when a face detected from the full image matches a face that has been registered in advance. In so doing, it is possible to record only partial videos of desired persons (i.e., registrants), even when a large number of people appear within the field of view.
However, if the above video recording apparatus relies on a selection method involving the size order of faces in the original image or using registered faces as feature points, then certain problems develop when attempting to implement the apparatus as a consumer video camera or similar product.
For example, in some cases the user may not have decided on the photographic subject in advance, and thus there is a problem in that the face that the user wants to record may not be registered. Furthermore, in cases such as when a large number of people are lined up at equal distances to the camera, the sizes of their respective faces become nearly uniform, and thus there is no guarantee that the user will be able to record the particular desired face.